Fluid Engine with Enhanced Efficiency

ABSTRACT

An engine provides torque by transmitting power in a fluid using optimally positioned lift-to-drag ratio blades with air-foil shape sections. The fluid may be liquid or gas. Various considerations of engine configuration, fluid density, fluid pressure and fluid temperature are design parameters that can be tuned to achieve high performance. The fluid flow created can be used to drive rotary motion of an output axle, for example.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to co-pending U.S. patent application (“Co-pending Patent Application”), Ser. No. 10/963,274, entitled “Method and System for Generation of Electrical and Mechanical Power using Sterling Engine Principles,” filed on Oct. 12, 2004, bearing Attorney Docket No. M-15504 US. The Co-pending patent application is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the energy conversion devices. In particular, the present invention relates to engines which efficiently transmitting mechanical energy into useful work through fluid motion.

2. Discussion of the Related Art

A heat engine operates by converting the heat energy which causes fluid flows between zones of different temperatures into useful work. A typical heat engine uses the heat energy to drive coordinated and reciprocating motion of a set of pistons or rotary motion of a set of turbine blades. The motion of the pistons or blades drives machinery or a generator.

In the prior art, moving parts for the heat engine operation are enclosed in a housing and coupled mechanically (e.g., by an axle) to external parts to drive external machinery.

Wings and airfoils take advantage of their shapes to obtain aerodynamic advantage in their movements in a fluid (e.g., air). There are many wing and airfoil designs available from many sources including on-line UIUC airfoil database and many more modern airfoils.

National Advisory Committee for Aeronautics (NACA) which designed and tested a variety of wing designs and published the results in a systematic set of tables. These results are still valid today which can be used in designing wings for many applications. The tables provide lift and drag coefficients for airfoils based upon the airfoils angle of attack to the fluid that it is flowing through. Using these coefficients lift and drag forces can be calculated using the following equations:

$\begin{matrix} {{Lift} = {\frac{1}{2}C_{l}\rho \; V^{2}A}} & \left. 1 \right) \\ {{Drag} = {\frac{1}{2}C_{d}\rho \; V^{2}A}} & \left. 2 \right) \end{matrix}$

where C₁ is the lift coefficient, C_(d) is the drag coefficient, ρ is the density of the fluid, V is the velocity of the airfoil relative to the fluid, and A is the area of the airfoil. The ratio of the lift to drag (L/D ratio) is used to compare the efficiency of an airfoil or blade design.

The ratio of the lift to the drag (L/D ratio) is used as a measure for the efficiency of lift creation of the airfoil or blade design at a specific angle of attack with specific fluid characteristics.

The minimum input power P_(in) required to drive a pump which has a discharge of Q, fluid pressure P_(pres), and a theoretical pressure head H_(T) is given by: P_(in)=QP_(pres)=QρgH_(T). Euler's turbomachine relation can be used to determine the pressure head created from a set of rotating blades; the pressure head is given by:

$H_{T} = \frac{{u_{2}V_{2}\cos \; \alpha_{2}} - {u_{1}V_{1}\cos \; \alpha_{1}}}{g}$

SUMMARY

According to one embodiment of the present invention, an engine provides efficiency by transmitting power in a fluid using optimally positioned lift-to-drag ratio aerodynamic blades to create a torque. The fluid may be liquid or gas. Various considerations of engine configuration, blade location, blade shape, lift-to-drag ratio of blade, blade angle, fluid density, fluid pressure, fluid path, fluid motion and fluid velocity are design parameters that can be tuned to achieve high performance. The fluid flow created can be used to drive rotary motion of an output axle, for example.

The present invention is better understood upon consideration of the detailed description below, in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a shows a cross section of fluid engine 100, in accordance with one embodiment of the present invention.

FIG. 1 b is a cross section of fluid engine 100, with upper portion 104 and lower portion 120 separated to show fluid structure 102 and radial blades 106.

FIG. 1 c shows a cross section of fluid engine 150, in accordance with an embodiment of the present invention.

FIG. 1 d is a perspective view showing the moving parts of fluid engine 100 of FIG. 1, without housing 110.

FIG. 2 is a perspective view showing the fluid engine 150 of FIG. 1 c, without housing 160.

FIG. 3 a shows a perspective view of fluid engine 300, in accordance with an embodiment of the present invention.

FIG. 3 b shows a second view of fluid engine 300, in accordance with an embodiment of the present invention.

FIG. 4 shows a perspective view of fluid engine 400, in accordance with an embodiment of the present invention.

FIG. 5 shows a perspective view of fluid engine 500, which incorporates fluid rotary engine 400 of FIG. 4.

FIG. 6 a shows orientations of blades 601 a, 601 b, 601 c and 601 d which are arranged axially to create torque about a center point.

FIG. 6 b shows blades 611 a and 611 b which are arranged radially to create torque about a center point.

FIG. 7 a shows spiral blades 766 a and 766 b, suitable for use in a fluid engine, according to an embodiment of the present invention.

FIG. 7 b shows spiral blade set 708, suitable for use in a fluid engine, according to an embodiment of the present invention.

FIG. 7 c shows spiral blades 767 a and 767 b suitable for use in a fluid engine, according to an embodiment of the present invention.

FIG. 8 a shows a cross section view of fluid engine 800, according to an embodiment of the present invention.

FIG. 8 b shows a cross section view of spiral blade 802 a of fluid engine 800.

FIG. 8 c shows fluid structure 820 of fluid engine 800.

To facilitate cross-referencing among the figures, like elements are assigned like reference numerals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A fluid engine is a device that converts fluid energy into mechanical energy. A fluid engine of the present invention operates by utilizing a lift force gain on an aerodynamic blade, from a drag force that resists the working fluid movement through the blade, to create torque for the fluid engine. The lift force on the blade results from the energy loss by the fluid from the drag force. The lift force creates a torque that sets into motion the movable parts of the fluid engine, thereby operating the fluid engine. An aerodynamic blade with a lift-to-drag ratio (L/D ratio) of 10 means the lift force is 10 times the drag force. According to the present invention, the fluid which flows inside fluid engine may be one or more gases or one or more liquids.

FIG. 1 a shows a cross section of fluid engine 100, in accordance with one embodiment of the present invention. As shown in FIG. 1, engine 100 includes housing 110, which includes upper portion 104 and lower portion 120. A fluid is typically sealed inside housing 110 for transmitting power from input axle 101 to the fluid inside fluid engine 100 which, in turn, creates lift for blades positioned inside fluid engine 100 to create torque. Motion induced by this torque provides the output power to output axle 113. Fluid structure 102 includes input axle 101 and radial blade set 106. Input axle 101 is driven externally to rotate radial blade set 106, which increases both the fluid rotational velocity and the pressure inside housing 110. Space 103 is provided to house appropriate bearings to facilitate rotation of fluid structure 102. Separator structure 111 is a torroidal structure having provided thereon axial blades 108. The lift force on axial blades 108 due to the motion of the fluid provides the torque output for fluid engine 100. Separator structure 111 may be an annular shape air-foil blade. In this embodiment, separator structure 111 is hollow inside (space 107) to reduce weight, and to provide room for placement of control elements. Axial blades 108 are preferably aerodynamic blades having lift-to-drag ratio of preferably much greater than one for engine efficiency. Axial blades 108 are positioned along the outer portion of separator structure 111, and each oriented to maximize torque creation from the fluid flow to drive output axle 113.

The rotational motion of radial blades 106 creates a centrifugal force that drives the fluid radially, such that a flow is created at an optimal “angle of attack” on each of axial blades 108, providing significant amount of torque to rotate separator structure 111. As shown in FIG. 1, separator structure 111 is structurally supported by support elements 112 to support base 109. Support base 109 may be used for controlling working fluid flow. Support elements 112 may be provided with blades (with air-foil shape sections) for torque creation. Alternatively, another set of blades may be provided in place of support elements 112 to provide additional torque. The motion of separator 111 is transmitted by support elements 112 to drive rotary motion of support base 109 and output axle 113, which is attached to support base 109. Bearings 114 ensure axial stability in output axle 113's rotation. In one embodiment, axial blades 108 are structurally attached to the interior walls of housing 110 and bearings 114 are eliminated. During operation, the working fluid flows across axial blades 108 to create a torque, which causes housing 101 to rotate in a predetermined direction. Rotary motion of engine 100 may be used to drive machinery through an axle or a gear structure coupled externally to the housing.

During operation, fluid structure 102 provides sufficient fluid pressure to compensate fluid pressure loss due to drag and friction in fluid circulation. Fluid exiting fluid structure 102 may have a rotational velocity (i.e., angular velocity and hence angular momentum) equal to or greater than the rotational velocity of axial blades 108 to maximize the efficiency of fluid engine 100. Output torque at output axle 113 is the sum of the torques generated by axial blades 108. Engine efficiency can be increased by orienting axial blades 108 such that the fluid flow acts on each blade in a preferred angle of attack, so as to utilize their lift-to-drag ratio to maximize the torque created.

Fluid structure 102, which includes blades 106 and an input axle 101, is located in upper portion 104, is designed to drive the working fluid mechanically and radially outward toward peripheral fluid space 131. Fluid structure 102 may function as an impeller, a pump, a compressor, a fan or a blower, depending on the configuration of blade set 106 and the applications of fluid engine 100. In one embodiment, fluid structure 102 may have adjustable blades or blade configurations such that blade set 106 provides energy for the working fluid to flow inside fluid engine 100. The force achieved in engine 100 can be controlled by adjusting the amount of fluid pumped by fluid structure 102.

The force created in the fluid increases with the density of the fluid used, according to the present invention. Therefore a higher fluid density (e.g., a liquid) results in a lower fluid velocity requirement to create a given output power. The input power requirement is a consideration during system design based on the tradeoffs between fluid density and fluid velocity. Fluid pressure loss due to friction, which increases with fluid velocity and fluid viscosity, and housing requirements should also be considered when choosing between a gas and a liquid.

FIG. 1 b is a cross section of fluid engine 100, with upper portion 104 and lower portion 120 separated to show fluid structure 102 and radial blades 106.

FIG. 1 c shows a cross section of fluid engine 150, in accordance with an embodiment of the present invention. Housing 160 of fluid engine 150 includes upper portion 164 and lower portion 170. A fluid is typically sealed inside housing 160 for transmitting power from input axle 113 ¹ to move fluid with blade set 203 inside engine 150 such that fluid drives axial blades 108, blades sets 166 a and 166 b to create torque for output axle 101. Fluid structure 109 includes input axle 113 and blade set 203. Input axle 113 is driven externally to rotate blade set 203, which increases both the fluid rotational velocity and the pressure inside housing 160. The rotational motion of blade set 203 creates a rotational fluid flow that drives the fluid to upper portion 164 through center fluid space 130 and which returns to lower portion 170 through peripheral fluid space 131 and then back to center fluid space 130. In this instance, unlike fluid engine 100, axle 113 is not the output axle, but the input axle that is driven externally. Axle 101 is the output axle in this instance. In general, the input and output axles can be interchangeable, depending on the engine's application. In this description, to avoid confusion, the structure that is linked to the input axle to impose a rotational force on to the fluid is referred to as a “fluid structure.”

In FIG. 1 c, fluid engine 150 is shown, for example only, without radial blades 106, but instead is provided blade set 166 (which includes blade set 166 a in the upper portion 164 and blade set 166 b in the lower portion 170) as support elements which secure separator 111 to the upper portion 164 and lower portion 170. Separator structure 111 is a torroidal structure having provided thereon axial blades 108, blade sets 166 a and 166 b. Separator structure 111 may be a portion of axial blades 108. In addition, separator 111 is also optional. One or more additional rings of blades (e.g., blades 171) may be provided for additional torque. Reactive blades may be used in blade set 166 to create torque. Blade set 166 a or 166 b may have spiral shape blades. Axial blades 108, blade set 166 a and 166 b are preferably aerodynamic blades having lift-to-drag ratio of preferably much greater than one. Blade sets 166 a and 166 b may be provided as support elements for fluid engine 150. Blade sets 166 a and 166 b are coupled to output axle 101. Blade sets 166 a and 166 b may be reactive type blades. In one embodiment, one of the axial blades 108, blade sets 166 a and 166 b is structurally attached to interior wall of housing 160 and a bearing 103 is eliminated. During operation, the working fluid flows across axial blades 108 to create a torque to cause housing 160 to rotate in a predetermined direction. Rotary motion of engine 160 may be used to drive machinery through an axle or a gear structure coupled externally to the housing.

In one embodiment, blades set 166 a, 166 b and axial blades 108 propel output axle 101 in a rotational motion to transmit the mechanical power output of fluid engine 150. Output axle 101 rotates in preferentially in one direction. Axial blades 108, blades set 166 a and 166 b rotate as a result of fluid flow pressure generated by fluid structure 109. According to another embodiment, blades inside fluid engine 150 rotate and create vortices in the working fluid such that the fluid flows in rotational motion around an axis. The velocity of the working fluid put the blades into motion, thus doing useful work. The torque in the rotary motion of the output axle 101 may be used to drive machinery.

FIG. 1 d is a perspective view showing the moving parts of fluid engine 100 of FIG. 1 a, without housing 110.

FIG. 2 is a perspective view showing the fluid engine 150 of FIG. 1 c, without housing 160. As shown in FIG. 2, provided within housing 110 are two sets of blades 166 a and 166 b, one set of axial blades 108 at peripheral, and blade set 203 provided on fluid structure 109. Preferably, axial blades 108 are aerodynamic blades having lift-to-drag ratio significantly greater than 1, and blade sets 166 a and 166 b are reaction or aerodynamic blades. In fluid engine 150, fluid structure 109 rotates at a speed independent of the speed in any of the three sets of blades (i.e. blades 166 a and 166 b, and axial blades 108). Input axle 113 runs through blade set 203. When blade set 203 is driven by the power output of fluid engine 150, gears may be used to set blade set 203's rotational speed at a specific ratio to fluid engine 150's output rotational speed. By appropriately setting gear ratios, blade set 203 can generate at times enough power to operate fluid engine 150. However, when blade set 203 is driven externally, gears are not needed, so that fluid structure 109's rotational speed is set by the rotational speed of the external driver or engine. In one embodiment, fluid structure 109 may be provided by a pump, a propeller, a compressor, a fan or a blower depending on the configuration of the set of blade and the applications of fluid engine.

In one embodiment, a fluid structure (e.g., fluid structure 102 or 109) may locate anywhere within the fluid engine to create a desirable fluid flow. More than one fluid structure or set of blades may be provided to drive the fluid to do work on blades. The fluid structure may include one or more mechanisms that allow the blades to be retracted from the fluid path (e.g., folded flat around the axle or to align along the interior wall of housing 110), when no mechanical input power is present to drive the fluid structure, so as to reduce fluid energy loss. In one embodiment, the blades inside the fluid structure may function as a diffuser to convert the rotational fluid to a high pressure fluid without rotation such that the fluid structure need not be continuously powered by an external mechanical power source.

Blades in the fluid structure may be powered by a spiral spring to rotate the fluid. In one embodiment, a torque created from the output axle of a fluid engine can be transmitted back to the input axle to power the fluid structure. Blades creating torque can form fluid passages. Each blade may be adjustable to control the torque generated by the blade. Adjustment may be implemented by controlling the angle of attack or by tilting the blade. Fluid engines 100 or 150 may be configured to be rotary fluid engines.

FIG. 3 a shows a perspective view of fluid rotary engine 300, in accordance with an embodiment of the present invention. As shown in FIG. 3 a, fluid rotary engine 300 includes housing 306 which encloses fluid chamber 307. Fluid chamber 307 opens to four extension chambers 301-304, made up of upper portions 301 u, 302 u, 303 u and 304 u and lower portions 301 b, 302 b, 303 b and 304 b, respectively. Inside fluid chamber 307 may be provided any of the fluid structures of the fluid engines (e.g., fluid engines 100 or 150) discussed above. In FIG. 3 a, fluid structure 109 includes blade set 203 and input axle 113 is shown. Fluid structure 109 creates a fluid circulation that flows from fluid chamber 307 to upper portions 301 u, 302 u, 303 u and 304 u of extension chambers 301-304 and back to chamber 307 through lower portions 301 b, 302 b, 303 b and 304 b of extension chambers 301-304. During operation, extension chambers 301-304 are enclosed. Inside each extension chamber are aerodynamic blades 305, which are suitably oriented to use the fluid flow to create torque, which causes rotation of the extension chambers 301-304 and drives output axle 101. FIG. 3 b shows a second view of fluid rotary engine 300, in accordance with one embodiment of the present invention. As shown in FIG. 3 b, aerodynamic blades 305 are oriented in upper portions 301 u, 302 u, 303 u and 303 u, and oriented in lower portions 301 b, 302 b, 303 b and 304 b to allow a torque to be created by extension chambers 301-304 on output axle 101. Fluid engine 300 is design for high torque, slow rotation to reduce the impact of centrifugal force on the returning fluid. According to the present invention, fluid structure 109 may be provided by a pump, a propeller, an impeller, a compressor, a fan or a blower depending on the configuration of the set of blade and the applications of fluid engine.

FIG. 4 shows a perspective view of fluid rotary engine 400, in accordance with an embodiment of the present invention. Fluid rotary engine 400 includes housing 404, which is made up of arms 404 l and 404 r and center portion 404 c, and which forms continuous fluid chamber 403. Fluid rotary engine 400 is an open system which starts fluid (gases or liquids) circulation with the centrifugal force created by the rotation of output axle 113 or arm 404 l or arm 404 r. The centrifugal force pulls fluid into center portion 404 c. During operation, fluid flows into center portion 404 c and moves outwardly toward arms 404 l and 404 r of chamber 403 by the centrifugal force and exits at nozzles 401 a and 401 b. Within fluid chamber 403 are provided lift-to-drag ratio aerodynamic blades 305, oriented to create torque from the fluid flow to drive a rotary mechanism (hence output power at output axle 113) attached to the center portion 404 c. Torque is created by the fluid exiting through nozzles 401 a and 401 b (i.e., by a reactive force on nozzles 401 a and 401 b as the fluid leaves nozzles 401 a and 401 b). Fluid rotary engines 400 may be configured as a closed system with sealed fluid chambers, Center portion 404 c may be positioned downward to pull fluid up into center portion 404 c.

FIG. 5 shows a perspective view of fluid rotary engine 500, in accordance with an embodiment of the present invention. Fluid rotary engine 500 is an open system. As shown in FIG. 5, fluid rotary engine 500 provides the torque in the system to drive output axles 101 and 113. Fluid rotary engine 500 includes an upper portion 502 a and lower portion 502 b. Lower portion 502 b may be provided by an open system type fluid engine, such as fluid engine 400 of FIG. 4. The fluid exiting from fluid chamber 403 through nozzles 401 a and 401 b in the lower portion 502 b of fluid engine 500 is directed to drive axial blades 501 in upper portion 502 a to provide additional torque to drive output axle 101. Axle 101 and axle 113 rotate in opposite direction. Fluid rotary engines 500 may be configured as a closed system with sealed fluid chambers. Gaseous fluid may be pressurized.

FIG. 6 a shows aerodynamic blades arranged axially and oriented to create torque. In FIG. 6 a, blade set 601, having blades 601 a, 601 b, 601 c and 601 d, is located to create a torque on axle 605 from a fluid flowing axially as indicated from fluid flows 604 a, 604 b, 604 c and 604 d. Blades 601 a, 601 b, 601 c and 601 d are positioned to create lift forces 602 a, 602 b, 602 c, 602 d respectively where each lift force is directed to maximize the torque created (i.e. perpendicular to the axis of rotation). Drag forces 603 a, 603 b, 603 c and 603 d due to the fluid flowing across aerodynamic blade set 601 are the fluid forces that create the torque generated by aerodynamic blade set 601. The angular velocity difference between each blade and the fluid flow (i.e. blade 601 a and fluid flow 604 a) determines the angle of attack of each blade. Blades 601 a, 601 b, 601 c and 601 d are positioned such that their angle of attack is greater than or equal to zero. For example, at blade 601 a, which has its lift force 602 a (LF) located at radius 606 a (R) from axle 605, drag force 603 a (DF) and has a lift-to-drag ratio of LD, the torque created by blade 601 a can be approximated by LF*R=DF*LD*R. Therefore, blade 601 a creates a torque using a force greater than the fluid force (drag force 603 a) when LD is greater than 1. Similarly, blades 601 b, 601 c and 601 d each generate a torque using a force greater than the fluid force.

FIG. 6 b shows aerodynamic blades arranged radially to create torque. In FIG. 6 b, blades 611 a and 611 b are located to create a torque around axis of rotation 620 from a fluid flowing radially outward as indicated by fluid flows 614 a and 614 b. Blades 611 a and 611 b are positioned to create lift forces 612 a and 612 b respectively and drag forces 613 a and 613 b respectively. Like the axially positioned blades described above, blades 611 a and 611 b can generate toques using a force greater than the fluid force if blades 611 a and 611 b have a lift to drag ratio greater than 1. As fluid flows radially outward, the fluid has reduced angular velocity due to conservation of angular momentum. This change of fluid angular velocity may affect the lift and drag forces generated by the blades oriented along the radial direction, such as blades 611 a and 611 b. Having a fluid with a higher angular velocity at the center than the angular velocity of a radially oriented blade's leading edge, such as leading edges 615 a and 615 b of blades 611 a and 611 b, may reduce these effects. Blades using airfoil sections that have high camber or using multiple sets of shorter blades may also reduce these effects.

According to the present invention, a blade with a lift-to-drag ratio greater than 1 can generate a lift force greater than a drag force when a fluid flows across the blade. The blade can be positioned within an enclosed engine to produce a force greater than the force required to move the fluid across the blade for torque creation.

According to another embodiment, fluid engine 700 is provided by modifying the structures of fluid engine 150. Specifically, fluid engine 700 is achieved by replacing blade set 166 a of fluid engine 150 with spiral blades 766 a and 766 b replacing axial blades 108 of fluid engine 150 with spiral blade set 708, and replacing blade set 166 b of fluid engine 150 with spiral blades 767 a and 767 b. Spiral blades 766 a and 766 b are shown in FIG. 7 a. Similarly, spiral blade set 708 and spiral blades 767 a and 767 b are shown in FIGS. 7 b and 7 c, respectively, Fluid engine 700 has a rotational fluid flow as shown in FIG. 1 c, fluid structure 109 includes blade set 203 and input axle 113. Input axle 113 is configured to rotate blade set 203 to drive fluid moving in the opposite direction as the curving direction of the spiral blades. In one embodiment, blade set 203 has aerodynamic blades which may be adjustable such that blade set 203 functions as a propeller. Therefore, the difference in the relative angular velocity between the fluid and the blades in blade set 203 determines the increase in fluid pressure.

When spiral fluid engine 700 starts up, input axle 113 rotates blade set 203 forcing fluid to move upward through center fluid space 130 into upper portion 164. Blades 766 a and 766 b in upper portion 164 force the fluid to rotate in the opposite direction as input axle 113 rotation. Rotational fluid flows from upper portion 164 to peripheral space 131 where axial blades 108, as shown in FIG. 7 b, cause fluid to flow helically downward into lower portion 170. Blades 767 a and 767 b in lower portion 170 increase the fluid angular velocity as the fluid moves inward to central fluid space 130. Blades 766 a, 766 b, 708, 767 a and 767 b in FIGS. 7 a, 7 b and 7 c, respectively, which are designed to create torque on output axle 101 from the lift force generated by the spiral fluid flow, rotate in the same rotational direction as the fluid. As the fluid continues to circulate in the manner described above, the fluid angular velocity increases, including the fluid angular velocity within center fluid space 130, so that the relative angular velocity between the fluid and blade set 203 also increases. The angular velocity of blade set 203 can be decreased as long as there is a sufficient relative angular velocity difference between the fluid and blade set 203 to increase fluid pressure to keep fluid circulation. When the fluid reaches a specific angular velocity, blade set 203 can be made stationary (i.e. input axle 113 doe not rotate), as blade set 203 have produced a sufficient fluid pressure increase to maintain fluid circulation.

According to another embodiment of the present invention, as shown in FIG. 8 a, fluid engine 800 is a circular tube includes tube housing 801, enclosing a working fluid, fluid structure 820 and helical blade set 802, including helical blades 802 a and 802 b. Tube housing 801 is coupled to output axle 811 through support element 812. Fluid structure 820 forces working fluid into helical flow path 810 along the interior wall of tube housing 801. Helical blade set 802 creates torque to rotate tube housing 801 which drives output axle 811 by blade lift forces such as lift force 803 a and 803 b created from the working fluid flowing along helical flow path 810. From FIG. 8 b, which shows helical blade 802 a, fluid flow 810 a flows across helical blade 802 a from leading edge 805 a helically across helical blade 802 a until reaching trailing edge 806 a. The lift force created by helical blade 802 a is in the direction pointed into page with drag force 804 a along the working fluid path across helical blade 802 a. Blades 802 a and 802 b in helical blade set 802 are designed to have a lift-to-drag ratio greater than 1.

In FIG. 8 c, fluid structure 820 includes axial blade set 822 attached to input axle 821 and stationary propeller 823 attached to interior wall of tube housing 801. After input fluid flow 810 b enters fluid structure 820, input axle 821 powers axial blade set 822 to increase the rotational velocity of input fluid flow 810 b. Working fluid leaving axial blade set 822 flows through stationary propeller 823 which uses the working fluid angular velocity to increase the working fluid pressure, so as to keep working fluid circulation around interior housing 801. Output fluid flow 810 c leaves fluid structure 820 after flowing through stationary propeller 823.

In one embodiment, adjustment of blade parameters may be implemented to enable adjustments on the angle of attack, surface area and turning with a range sufficient to maximize L/D ratio or lift force generated by the blade. Blades that create torque may be tilted, adjusted in referencing the fluid flow direction, fluid velocity and fluid motion to maximize the torque creation. Blades may be adjusted to have horizontal movement, up or down, and turning. The fluid engine's thrust output may be maximized by altering the wing reference area, angle of attack.

In one embodiment of present invention, blades creating torque are coupled to interior wall of housing of a fluid engine, the housing of the fluid engine rotates. As discussed above, fluid engine 100 and fluid engine 150 can be rotary engines. The rotary motion of the rotary engines may be used to create thrust or torque. The blades creating torque may be located in anywhere where torque creation can be achieved. In another embodiment, the blades inside the housing of a fluid engine may form continuous or discontinuous, enclosed or unenclosed channels for working fluid to flow across. A fluid structure for driving fluid flow may be used in each channel.

Working fluid flowing across the blades at an optimum angle of attack and high lift-to-drag ratios can maximize the torque created by the blades. The amount of power output to run a fluid engine is the fluid angular velocity difference between the outward flow and the inward flow of the fluid structure.

Blades shown in figures are positioned to best demonstrate the present invention. These figures show aerodynamic blades having zero angle of attack and other blades being straight. Blade geometry and position are dependent on many engine design parameters including the fluid flow path, fluid motion, fluid velocity and blade angle of attack to create greatest lift-to-drag ratio.

Wings, blade with air-foil shape sections and airfoil means objects with aerodynamic effects in this application. Any object with aerodynamic effect may be suitable to implement present invention. According to the present invention, working fluid inside a fluid engine moved by a fluid structure (a structure having an axle and a set of blades) may function as an impeller, a propeller, a pump, a compressor, a fan or a blower, depending on the configuration of the set of blade and the applications of fluid engine applications. Some examples of such a fluid structure are fluid structure 102 of fluid engine 100, fluid structure 109 of fluid engine 150 and fluid structure 109 of fluid engine 300. In one embodiment, blade set of a fluid structure may be located in peripheral fluid space 131.

According to the present invention, blades creating torque and blades moving fluid may be coupled to the same axle. According to the present invention, blades creating torque and blades moving fluid may be coupled to or arranged on the same internal structure of a fluid engine.

In one embodiment, gases are used as the working fluid to circulate inside fluid engines. Fluid circulation inside fluid engines can be powered by heat energy. Fluid engines may convert heat energy to rotational mechanical energy by heating in one or more areas and cooling in one or more areas. The fluid engine may therefore maintain a temperature difference to keep flow circulation.

According to another embodiment of the present invention, heat engines, powered by heat energy with two areas inside the fluid engines with a temperature difference, can also benefit from using aerodynamic blades as previously described. The temperature difference between two areas inside the heat engine is used to keep fluid circulation within the engine. Torque generated by a heat engine can be created by the working fluid flowing across one or more aerodynamic sets of blades in configurations similar to fluid engines in accordance to the present invention.

Heat engine 1000, which is powered using heat energy, is constructed by modifying structures of fluid engine 100. Fluid structure 102 of fluid engine 100 (includes input axle 101 and radial blades 106) is replaced with one or more heating areas in upper portion 104 and one or more cooling areas in lower portion 120. Radial aerodynamic blades 106 in upper portion 104 and a set of similar aerodynamic blades in lower portion 120 may be provided to create torque. Separator 111 is used as an insulator between heating area in upper portion 104 and cooling area in lower portion 120. Working fluid inside upper portion 104 moves outward toward peripheral fluid space 131 then moves from peripheral fluid space 131 to center fluid space 130 through lower portion 120 to form circulation of fluid flow. Torque is created by working fluid flowing across axial blades 108, radial aerodynamic blades 106, support elements 112 (may be blades with aerodynamic effect) and any aerodynamic blades configured to contribute to generating torque.

In one embodiment, heat engine 1000 has a fluid circulation in upper portion 104 that moves inward toward center fluid space 130, moves to lower portion 120 through center fluid space 130, and moves from lower portion 120 to upper portion 104 through peripheral fluid space 131. Aerodynamic blades can be placed at any suitable location to create torque for heat engine 1000. In one embodiment, heat engine 1000 has working fluid rotating from upper portion 104 to lower portion 120 through peripheral fluid space 131 and rotating from lower portion 120 to upper portion 104 through center fluid space 130, as a result of the rotation of axial blades 108 and radial aerodynamic blades 106. Rotational fluid flow from upper portion 104 to lower portion 120 creates a downward draft surrounding an upward draft created by rotational fluid flow from lower portion 120 to upper portion 104. Rotational fluid flow may induce a spiral fluid flow.

In one embodiment, heat engine 1500 powered by heat energy can be constructed by modifying fluid engine 150 by replacing fluid structure 109 with one or more heating areas in upper portion 164 and one or more cooling areas in lower portion 170. Axial aerodynamic blades may be oriented in center fluid space 130, radial aerodynamic blades 166 a and 166 b may be placed separately in upper portion 164 and lower portion 170 to create torque.

In one embodiment, heat engine 3000 powered by heat energy can be constructed by replacing fluid structure 109 (include input axle 113 and blade set 203) of fluid engine 300 with heating mechanism in peripheral portion of extension chambers 301, 302, 303 and 304, and providing cooling mechanism in a lower portion of fluid chamber 307. The temperature difference in heat engine 3000 causes fluid flows from a lower portion of fluid chamber 307 outwardly toward lower portions 301 b, 302 b, 303 b and 304 b by centrifugal force created by the rotation of the heat engine 3000. Fluid then flows toward upper portions 301 u, 302 u, 303 u and 304 u with centrifugal force created by rotational motion of heat engine 3000. The fluid expands in the peripheral portion of extension chambers 301, 302, 303 and 304 and travels back to fluid chamber 307 through upper portions 301 u, 302 u, 303 u and 304 u. Aerodynamic blades 305 create torque when the fluid flows across and rotates heat engine 3000.

Heating and cooling elements can be embedded in aerodynamic blades, support elements, separator or structures inside housing to change the velocity of fluid and the density of fluid for maximizing lift force for torque creation. Fluid volume control mechanism may be used to alter fluid velocity for aerodynamic blades.

The above detailed description is provided to illustrate specific embodiments of the present invention and is not intended to be limiting. Numerous variations and modifications within the scope of the present invention are possible. The present invention is set forth in the accompanying claims. 

1. An engine, comprising: a housing including an interior space divided into a first portion and a second portion that are connected with each other; a working fluid filling the interior space which flows, during operation, between the first portion and the second portions; and one or more airfoils positioned within the interior space in the circulation path of the fluid flow.
 2. An engine as in claim 1 wherein, during operation, a temperature difference is created between the first portion and the second portion, such that the working fluid flows between the first portion and the second portion.
 3. An engine as in claim 2, wherein the temperature difference is to achieve a fluid flow velocity within the interior space.
 4. An engine as in claim 1 wherein, during operation, a propeller drives the working fluid between the first portion and the second portion.
 5. An engine as in claim 1, wherein the airfoils are positioned relative to the fluid flow to creates torque.
 6. An engine as in claim 1, wherein a fluid structure drives the working fluid between the first portion and the second portion.
 7. An engine as in claim 6, wherein the fluid structure is driven by a power source.
 8. An engine as in claim 6, wherein the fluid structure comprises blades positioned to increase fluid pressure in the fluid flow.
 9. An engine as in claim 8, wherein the blades comprise reaction blades.
 10. An engine as in claim 8, wherein the blades comprise aerodynamic blades.
 11. An engine as in claim 1, wherein the first portion and the second portion is connected by a central portion and a peripheral portion.
 12. An engine as in claim 11, wherein the airfoils are positioned at the peripheral portion.
 13. An engine as in claim 1, wherein airfoils are positioned to create a lift force in a predetermined direction.
 14. An engine as in claim 13, wherein the predetermined direction is a direction of rotational motion resulting from the lift force.
 15. An engine as in claim 1, wherein the airfoils comprise axial blades.
 16. An engine as in claim 1, further comprising support structure securing airfoils to the housing.
 17. An engine as in claim 16, wherein the airfoils further comprise axial blades.
 18. An engine as in claim 1, wherein a portion of the airfoils form the support structures.
 19. An engine as in claim 1, wherein the airfoils comprise radial blades.
 21. An engine as in claim 1, wherein the airfoils are provided on interior walls of the housing, such that the lift force puts the housing into rotation motion,
 22. An engine as in claim 11, wherein the peripheral portion opens into a plurality of extension chambers, wherein a portion of the airfoils is placed in the extension chambers to provide torque.
 23. An engine as in claim 24, wherein each extension chamber includes a nozzle through which the working fluid leaves the extension chamber.
 24. An engine as in claim 22, wherein the fluid flow over the portion of the airfoils placed in the extension chambers create torque that drives a rotational motion of the housing to drive an output axle.
 25. An engine as in claim 23, wherein the working fluid leaving the extension chamber is directed towards a set of objects provided on a rotatable structure, such that the working fluid flowing over the set of the objects provides torque to the engine.
 26. An engine as in claim 11, wherein each extension chamber has a first opening and a second opening into the peripheral portion, and wherein fluid flow from the peripheral portion into the extension chamber through the first opening and from the extension chamber into the peripheral portion through the second opening.
 27. An engine as in claim 26, wherein fluid circulates between each extension chamber and the peripheral portion.
 28. An engine as in claim 22, wherein the torque provided by airfoils in the extension chamber sets the housing into rotational motion to drive an output axle.
 29. An engine as in claim 1, wherein the lift-to-drag ratio of an airfoil is greater than one.
 30. An engine as in claim 1, wherein an angle of attack of an airfoil, relative to the working fluid flow, is adjustable.
 31. An engine as in claim 30, wherein the angle of attack is adjustable to achieve a better torque.
 32. An engine as in claim 1, wherein an angle of attack of an airfoil is adjustable.
 33. An engine as in claim 1, wherein the airfoils comprise spiral blades.
 34. An engine as in claim 1, wherein the housing comprises a tubular portion rotatable about an axis.
 35. An engine as in claim 1, wherein the working fluid comprises a gas.
 36. An engine as in claim 35, wherein the gas is pressurized. 